Cigarette filter

ABSTRACT

A cigarette filter has filter sections including filter materials individually wrapped with plug wrap paper, forming paper for wrapping the filter sections integrally, and tipping paper covering the forming paper so as to connect the filter sections to a cigarette section to form a cigarette, wherein activated charcoal and silica/alumina are contained as adsorbents in at least one of the filter materials and a space between the filter materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a Continuation Application of PCT Application No.PCT/JP02/07808, filed Jul. 31, 2002, which was not published under PCTArticle 21(2) in English.

[0002] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2001-235202, filed Aug.2, 2001, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to an improved cigarette filtercapable of singularly adsorbing specified components contained inmainstream smoke.

[0005] 2. Description of the Related Art

[0006] Japanese Patent Disclosure (Kokai) No. 63-160659, for example,discloses a deodorizing agent (adsorbing agent) consisting of aninorganic mineral-based porous material carrying ferroussulfate/L-ascorbic acid. The document also discloses an example of afilter for a cigarette in which the deodorizing agent is contained.

[0007] However, the adsorbent disclosed in the document is intended toadsorb mainly ammonia, and it is not described at all in the documentwhat components of the mainstream smoke are removed in the case wherethe adsorbent is contained in the cigarette filter. In general, in thecase of using a filter containing an adsorbent capable of unselectivelyadsorbing various components contained in the mainstream smoke, it isknown to the art that the taste and flavor of the cigarette areadversely affected.

BRIEF SUMMARY OF THE INVENTION

[0008] An object of the present invention is to provide a cigarettefilter, which permits prominently suppressing adverse effect on thetaste and flavor of a cigarette and which permits selectively removingspecified components contained in mainstream smoke.

[0009] A cigarette filter according to the present invention comprises:filter sections including filter materials individually wrapped withplug wrap paper; forming paper for wrapping the filter sectionsintegrally; and tipping paper covering the forming paper so as toconnect the filter sections to a cigarette section to form a cigarette,wherein activated charcoal and silica/alumina are contained asadsorbents in at least one of the filter materials and a space betweenthe filter materials.

[0010] In the cigarette filter of the present invention, the plug wrappaper or the forming paper may contain the activated charcoal and thesilica/alumina as the adsorbents.

[0011] The cigarette filter according to the present invention hasactual structures including, for example, (1) a structure that twofilter materials are provided and a mixture of the activated charcoaland the silica/alumina is loaded in the space between the two filtermaterials, (2) a structure that two filter materials are provided and amixture of the activated charcoal and the silica/alumina is dispersed inone of the filter materials, (3) a structure that three filter materialsare provided and the activated charcoal and the silica/alumina areindividually loaded in the two spaces between the three filtermaterials, and (4) a structure that three filter materials are providedand the activated charcoal is dispersed in one filter material and thesilica/alumina is dispersed in another filter material.

[0012] Another cigarette filter according to the present inventioncomprises a cigarette holder body including filter materials arrangedtherein, wherein activated charcoal and silica/alumina are contained asadsorbents in at least one of the filter materials and a space betweenthe filter materials.

[0013] Incidentally, the structure of the cigarette filter according tothe present invention is not limited to those exemplified above, andvarious modifications are conceivable.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0014]FIG. 1 schematically shows an example of a structure of acigarette filter according to the present invention;

[0015]FIG. 2 schematically shows another example of a structure of acigarette filter according to the present invention;

[0016]FIG. 3 schematically shows another example of a structure of acigarette filter according to the present invention;

[0017]FIG. 4 schematically shows a further example of a structure of acigarette filter according to the present invention; and

[0018]FIG. 5 is a cross-sectional view of a cigarette holder to whichthe cigarette filter according to the present invention is applied.

DETAILED DESCRIPTION OF THE INVENTION

[0019] In the present invention, attention is paid to pyrazines andphenols as specified components contained in mainstream smoke of acigarette.

[0020] The present inventor has found that, where activated charcoal andsilica/alumina are used in combination as adsorbents for the cigarettefilter, these adsorbents produce a synergetic effect so as to singularlyremove the specified components contained in the mainstream smoke,thereby accomplishing the present invention.

[0021] The filter materials used in the present invention include, forexample, acetate, paper, and an unwoven fabric. As the activatedcharcoal of the adsorbents, coconut shell activated charcoal may beused. As the silica/alumina of the adsorbents, a product marketed underthe trade name of “Kyoward 700SN” by Kyowa Chemical Industry Co., Ltd,for example, may be used. The product contains 63.0% by weight of SiO₂and 10.3% by weight of Al₂O₃ and has weight loss on drying of 14.5% byweight.

[0022] In the present invention, the amount of the activated charcoaland the silica/alumina is set as follows: where the adsorbents arecontained in the filter material, the total amount of the adsorbentsshould be set to 1 mg to 150 mg, preferably 20 mg to 60 mg, per 10 mm ofthe filter material, and where the adsorbents are contained in the spacebetween the filter materials, the total amount of the adsorbents shouldbe set to 5 mg to 300 mg, preferably 30 mg to 120 mg per 5 mm of thespace.

[0023] Examples of the present invention will now be described.

[0024] A cigarette filter as a control without containing any adsorbentwas prepared as follows. Two filter materials (plain filters) wereprepared by forming acetate having a filament fineness of 2.2 denier anda tow fineness of 40,000 denier to have a length of 10 mm, and thefilter materials were wrapped with plug wrap paper, respectively, so asto obtain two filter sections. Two filter materials were arranged tohave a 5-mm space formed therebetween, and the two filter sections werewrapped with forming paper without loading any adsorbent in the space.The ventilation resistance of the filter was found to be 80 mmH₂O (1050mL/min).

[0025]FIG. 1 shows an example of a cigarette filter prepared in thisExample. The cigarette filter 1 was prepared as follows. Two filtermaterials (plain filters) 2 were prepared by forming acetate having afilament fineness of 2.2 denier and a tow fineness of 40,000 denier tohave a length of 10 mm, and the filter materials were wrapped with plugwrap paper, respectively, so as to obtain two filter sections. Twofilter materials 2 were arranged to have a space formed therebetween,and the two filter sections were wrapped with forming paper under thestate that a mixture of 30 mg of activated charcoal 41 and 30 mg ofsilica/alumina (trade name: Kyoward 700SN) 42 as adsorbents 4 was loadedin the space. In this case, the space was controlled to permit theadsorbents to have an apparent density of 100%.

[0026] For references, cigarette filters were also prepared with loading30 mg of activated charcoal alone or 30 mg of silica/alumina alone as anadsorbent in the space.

[0027] Also, cigarette filters were prepared with loading 60 mg ofactivated charcoal alone or 60 mg of silica/alumina alone, i.e., anadsorbent two times as much as that in the cigarette filters notedabove, in the space.

[0028] Each of the above cigarette filters was connected with a tape toa cigarette section prepared by wrapping cut tobacco with wrapper paperso as to prepare various cigarettes for experiments differing from eachother in the type of the adsorbent as shown in Table 1. A commercialcigarette rod was used for the cigarette section. A test for collectingthe mainstream smoke was applied to these cigarettes as follows.

[0029] The cigarette was connected to an automatic smoking machine witha tube (made of Tygon). A Cambridge filter was not provided. Theautomatic smoking machine was allowed to smoke the cigarette under thestandard smoking conditions, with the combustion length set at 40 mm.The mainstream smoke from the exhaust port was collected in a gas bag(made of Tedlar) having He put therein in advance, and then the innervolume of the gas bag was adjusted with He to be 8 L in total. Fifty mLof the gas taken from the gas bag was analyzed by gas chromatography.

[0030] Attention was paid to pyrazines, phenols, hydrocarbons andketones as specified components of the mainstream smoke, and dataanalysis of each of the specified components was performed based on thepeak area on the gas chromatograph. Table 1 shows the penetration ofeach of the pyrazines and phenols. The penetration Ta of each of thesespecified components is represented by:

Ta=Aa/Acnt,

[0031] where Acnt denotes the peak area of the specified component onthe gas chromatograph in the case where the adsorbent was not used (thecontrol), and Aa denotes the peak area of the specified component on thegas chromatograph in the case of using the adsorbent “a”. Each measuredvalue shown in Table 1 was obtained on the basis of the peak area of thespecified component on the gas chromatograph.

[0032] Also, the predicted value of the penetration for the filter using60 mg of activated charcoal denotes the square of the measured value ofthe penetration for the filter using 30 mg of activated charcoal.Similarly, the predicted value of the penetration for the filter using60 mg of silica/alumina denotes the square of the measured value of thepenetration for the filter using 30 mg of silica/alumina.

[0033] On the other hand, the predicted value of the penetration in thecase of using the two types of the adsorbents shown in Table 1 denotesthe calculated value of the penetration estimated from the penetrationfor the adsorbent in the case of using singly each of the two types ofthe adsorbents. To be more specific, the predicted value is representedby (Ta×Tb), where Ta denotes the penetration (measured value) of thespecified component in the case of using the adsorbent “a”, and Tbdenotes the penetration (measured value) of the specified component inthe case of using the adsorbent “b”.

[0034] If the measured value of the penetration in the case of using aplurality of different types of adsorbents in combination is prominentlysmaller than the predicted value, it can be judged that the specifiedcomponents are singularly adsorbed, which supports the synergetic effectproduced by the combination of the plurality of types of the adsorbents.Table 1 shows the results of the above experiments. TABLE 1 PenetrationPyrazines Phenols Measured Predicted Measured Predicted Adsorbent valuevalue value value None 1.00 1.00 Activated charcoal 0.60 0.68 (30 mg)Silica/alumina (30 mg) 0.73 0.61 Activated charcoal 0.38 0.36 0.48 0.46(60 mg) Silica/alumina (60 mg) 0.54 0.53 0.38 0.37 Mixture of activated0.22 0.44 0.30 0.41 charcoal (30 mg) and silica/alumina (30 mg) (total60 mg)

[0035] Where the activated charcoal alone was used twice as much orwhere silica/alumina alone was used twice as much, a significantdifference was not recognized between the measured value and thepredicted value.

[0036] A difference between the measured value and the predicted valuewas small in respect of hydrocarbons and ketones (not shown in Table 1),and thus, a synergetic effect produced by combination of plural types ofadsorbents was not recognized.

[0037] To the contrary, where the combination of the activated charcoaland the silica/alumina was used as the adsorbents, the measured valueswere markedly smaller than the predicted values in respect of pyrazinesand phenols as shown in Table 1, which clearly supports that asynergetic effect on the singular adsorption of these specifiedcomponents was produced.

[0038] From the results given above, if the specified components ofpyrazines and phenols are to be effectively adsorbed by using theactivated charcoal alone or the silica/alumina alone, it is necessary tofurther increase the amount of the adsorbent. In this case, it isexpected that the flavor and taste of the cigarettes are markedlyaffected. On the other hand, in the case of using in combination theactivated charcoal and silica/alumina as the adsorbents, it is expectedthat the specified components of pyrazines and phenols may be adsorbedeffectively even if the amount of the adsorbents is small, and thus, theflavor and taste of the cigarette are less affected.

[0039]FIG. 2 shows another example of a cigarette filter according tothe present invention. The cigarette filter 1 was prepared as follows:preparing three filter materials (plain filters) 2; forming three filtersections by wrapping plug wrap paper 3 around each of the filtermaterials 2; loading individually activated charcoal 41 andsilica/alumina (trade name: Kyoward 700SN) 42 as adsorbents 4 in thespace on the cut tobacco side and in the space on the mouth side betweenthe three filter sections; and wrapping forming paper 5 around the threefilter sections. In FIG. 2, the activated charcoal 41 was loaded in thespace on the mouth side and the silica/alumina was loaded in the spaceon the cut tobacco side. To the contrary, however, the silica/alumina 42may be loaded in the space on the mouth side and the activated charcoalmay be loaded in the space on the cut tobacco side.

[0040]FIG. 3 shows still another example of a cigarette filter accordingto the present invention. The cigarette filter 1 was prepared asfollows: preparing a filter material (plain filter) 2 obtained byforming acetate and another filter material 21 obtained by formingacetate having adsorbents of activated charcoal 41 and silica/alumina 42dispersed therein; forming two filter sections by wrapping plug wrappaper 3 around each of the filter materials 2 and 21; and wrappingforming paper 5 around the two filter sections.

[0041]FIG. 4 shows still another example of a cigarette filter accordingto the present invention. The cigarette filter 1 was prepared asfollows: preparing a filter material (plain filter) 2 obtained byforming acetate, a filter material (charcoal filter) 21 obtained byforming acetate having activated charcoal as an adsorbent dispersedtherein, and a filter material 22 obtained by forming acetate havingsilica/alumina as an adsorbent dispersed therein; forming three filtersections by wrapping plug wrap paper 3 around each of the filtermaterials 2, 21 and 22; and wrapping forming paper 5 around the threefilter sections. The arrangement of the filter materials 21 and 22 isnot particularly limited. It is possible to arrange any of these filtermaterials on the cut tobacco side.

[0042] Further, in the cigarette filter according to the presentinvention, it is possible to add activated charcoal and silica/aluminaas adsorbents to the forming paper.

[0043] The cigarette filter according to the present invention can beapplied in the form of a cigarette holder as shown in FIG. 5. Thecigarette holder comprises a cylindrical cigarette holder body 51 havinga mouth-end section 52 formed at one end, two filter materials 2arranged inside the cigarette holder body 51, and a mixture of activatedcharcoal 41 and silica/alumina 42 as adsorbents 4 loaded in the spacebetween the two filter materials 2.

[0044] The cigarette filter shown in FIG. 5 is obtained by applying thestructure shown in FIG. 1 to a cigarette holder. Likewise, it ispossible to apply the structure shown in each of FIGS. 2 to 4 to acigarette holder.

[0045] In the cigarette filter of any of the types described above, asynergetic effect is produced by the activated charcoal and thesilica/alumina so as to singularly adsorb pyrazines and phenols.

[0046] According to the present invention, it is possible to provide acigarette filter, which permits selectively removing specifiedcomponents contained in mainstream smoke while suppressing the effect onthe flavor and taste of the cigarette to a minimum.

What is claimed is:
 1. A cigarette filter, comprising: filter sectionsincluding filter materials individually wrapped with plug wrap paper;forming paper for wrapping the filter sections integrally; and tippingpaper covering the forming paper so as to connect the filter sections toa cigarette section to form a cigarette, wherein activated charcoal andsilica/alumina are contained as adsorbents in at least one of the filtermaterials and a space between the filter materials.
 2. The cigarettefilter according to claim 1, wherein the plug wrap paper or the formingpaper contains the activated charcoal and the silica/alumina as theadsorbents.
 3. The cigarette filter according to claim 1, wherein twofilter materials are provided, and a mixture of the activated charcoaland the silica/alumina is loaded in the space between the two filtermaterials.
 4. The cigarette filter according to claim 1, wherein twofilter materials are provided, and a mixture of the activated charcoaland the silica/alumina is dispersed in one of the filter materials. 5.The cigarette filter according to claim 1, wherein three filtermaterials are provided, and the activated charcoal and thesilica/alumina are individually loaded in the two spaces between thethree filter materials.
 6. The cigarette filter according to claim 1,wherein three filter materials are provided, and the activated charcoalis dispersed in one filter material and the silica/alumina is dispersedin another filter material.
 7. A cigarette filter, comprising acigarette holder body including filter materials arranged therein,wherein activated charcoal and silica/alumina are contained asadsorbents in at least one of the filter materials and a space betweenthe filter materials.